You can purchase these washers from any hardware store for about .50 to .70 cents

WHATTTTT !!!!----- I get a hundred ringbinder rings for $5 -- thats 5c a ring -- you are blowing money man!!!
Naa it is a great idea and easily removable. Great comparison photos.
One comment tho ( and sort of the same as Transits) but to do with the depth of rubber material. Your iris is thick enough that there is an extra surface to reflect light compared to the ringbinder ring. Experiment with buckling the iris away from the lens and the inside of the iris orifice is then out of sight of the lens.
This could increase contrast and change the stop slightly.
It could also incur vignetting.
Great work
Baz

WHATTTTT !!!!----- I get a hundred ringbinder rings for $5 -- thats 5c a ring -- you are blowing money man!!!
Naa it is a great idea and easily removable. Great comparison photos.
One comment tho ( and sort of the same as Transits) but to do with the depth of rubber material. Your iris is thick enough that there is an extra surface to reflect light compared to the ringbinder ring. Experiment with buckling the iris away from the lens and the inside of the iris orifice is then out of sight of the lens.
This could increase contrast and change the stop slightly.
It could also incur vignetting.
Great work
Baz

Yes, but you buy one washer and that's it, set it and forget it.
Good point about the thickness of the iris, I tried your suggestion by buckling it away from the lens, I really didn't notice any difference in the test shots. Maybe some matt paint will help.
Thank you for your suggestions, and thanks again for your posts, after all, you gave me this idea.

F1.4 and 35mm FOV? Wow! Can you change the aperture setting or are you stuck with f1.4?
Anyhow it looks sharp. This is a very nice lens and it looks good on the Q.

Jacob

Hi Jacob:

You can change the aperture (as there is an aperture ring) up to f/22 but there's no marking of f-stop. Cosmicar brand tend to be sharp. Anyhow I bought the len for $6.5 and paid $5.5 shipping. 35mmm is a good field of view, not too wide as the Rainbow 3.5mm which is ~20mm field of view. Again as noted, this len is a CS-mount and you will need a Pentax Q body cap and make an opening hole to mount the len.

Amazing modification for the Q! Never expected to see the Q with a turret full of lenses. It is like a glass bouquet. Rendition, you have multipled the Q fun factor by 3. Bet everyone gives this a double take when you are out shooting. Love it.
thanks for sharing
barondla

Amazing modification for the Q! Never expected to see the Q with a turret full of lenses. It is like a glass bouquet. Rendition, you have multipled the Q fun factor by 3. Bet everyone gives this a double take when you are out shooting. Love it.
thanks for sharing
barondla

Thanks guys. I am having a lot of fun converting old lens and with Q. Also, here is my recent custom converted Chimeric Pandora-6 (head is Russian 8mm movie len Pandora-6, tail is Russian 8mm movie len Meteor-8) mounted on Pentax Q. Len's marking indicated 9-25mm f/1.8 but since it is a combined len, the actual focal length is 15-35mm. It makes great vintage footage on Q.

Len shows chromatic aberration under bright day light. Here's an indoor test shot during the day

Frankar ~7mm-35mm D-mount made of various len parts, mainly from meteor-8M and Kodak Ektanon parts.I managed to lengthening the focusing distant and able to create a D-mount also. It showed sharp image center. Screws are for zoom handling